JP5153763B2 - Method and apparatus for analyzing isotope ratio - Google Patents

Description

  In the present invention, at least one sample gas and / or at least one standard gas is supplied to at least one analyzer via at least one open split, and a carrier gas can be added. , Relates to a method for analyzing isotope ratios. The invention further comprises an open split, the open split having a mixing area and a waiting area, wherein a capillary for the sample gas, carrier gas and / or standard gas, a capillary for taking out the gas, In particular the method described above, in which a capillary for supplying gas to the analyzer is arranged in the waiting area, where the capillary can be moved into or out of the mixing area. The invention relates to an apparatus for supplying gas to at least one analytical device for implementation.

  A feature of the apparatus for measuring isotope ratios is that all components must be configured so that no fractionation occurs. This separation occurs wherever transport occurs, for example by diffusion.

For example, Patent Document 1 discloses an open split as an interface between a mass spectrometer (isotope mass spectrometer or IRMS) suitable for isotope ratio analysis and a gas chromatography apparatus. This Patent Document 1 describes the analysis of CO2 and N2 when helium is used as a carrier gas. The amount of carrier gas supplied can be varied so that the dilutions of both gases to be analyzed can be matched to each other. The amount of carrier gas is changed through an appropriate valve or by changing the position of a capillary inserted into an open split. The operator needs a great deal of experience to be able to adjust the various gas flows and gas volumes correctly according to the results to be obtained. The analysis results depend on the operator's dexterity and vary more or less accidentally.
German Patent Application Publication No. 4333208A1

  The object of the present invention is to improve the method described at the outset for analyzing isotope ratios. In particular, the analysis results should more accurately represent the actual ratio.

  The method according to the invention is characterized in that the concentration of the sample gas and / or standard gas reaching the analyzer is adjusted by supplying the respective carrier gas or by supplying the sample gas directly to the analyzer. . Adjustments are preferably made by computer control, in particular by feedback based on sensor information and / or by repeating previously used parameters. The concept of adjustment should in principle be interpreted broadly and includes adjustment or control without feedback and adjustment in the narrow sense of feedback (as in automation technology). The adjustment can be realized by software or hardware. The adjustment is preferably program-controlled. As such a known adjuster for at least the carrier gas, for example, an electronically adjustable valve and / or actuator for a capillary entering an open split is adjusted. Adjustment also includes the possibility of adjusting the carrier gas supply to zero. Furthermore, the sample gas and the standard gas can already contain a carrier gas before entering the open split (preliminary gas mixture).

  The analyzer is preferably a mass spectrometer, in particular a mass spectrometer (IRMS) suitable for isotope ratio measurements. However, the present invention is not limited to this. Other, for example, optical analyzers, spectrometers, interferometers, spectrometers, etc. can be used.

  In an advantageous embodiment of the invention, the open split for at least one of the gases, i.e. sample gas, carrier gas, standard gas, comprises capillaries with different effective flow rates and the desired flow rate The gas flow is regulated by selecting and actuating a capillary with Additionally or alternatively, the gas flow is adjusted by other methods, such as adjustable valves. Initially, rough adjustments can be made based on a predetermined capillary selection, and fine adjustments can be made by appropriate actuators. Different effective flow rates of the individual capillaries are caused, for example, by different cross-sectional areas or lengths of the capillaries or, for example, by specific cross-sectional contractions at the end portions of the capillaries. Multiple capillaries can be provided for each gas.

  It is advantageous if only the inflow of the carrier gas is adjusted in each case and the remaining gas flow remains unregulated. This measure simplifies the device structure and the switching or programming technical work in the adjustment system.

  Advantageously, the supply of carrier gas is changed in stages so that parallel carrier gas split flows of the same or different scale can be actuated and combined with each other and the resulting single carrier gas flow can be adjusted.

  It is advantageous if the inflow of the carrier gas is adjusted in each case so that the concentration of the sample gas and / or the standard gas remains substantially constant, at least in the measurement range optimum for the analyzer. The volumetric flow rate of the sample gas varies depending on the source used. For example, it is known to supply gas from a gas chromatograph or elemental analyzer. In so doing, the amount of sample varies within the gas stream flowing through the sample capillary into the open splitter. This can be offset by a corresponding flow of carrier gas, so that the sample gas always reaches the optimum concentration for the analyzer. The same applies to the standard gas.

  For many applications, particularly for accurate dilution of standard gases, it is advisable to pre-record the relationship between dilution control and analyzer signal and to use pre-calibrated adjustments directly in the measurement process. This is extremely effective in connection with the gradual flow adjustment / control according to the present invention described later. That is, readjustment during the original measurement process can be completely eliminated.

  In another advantageous embodiment of the invention, the inflow of the respective carrier gas is adjusted during alternating successive measurements so that the sample gas and the standard gas provide a signal of approximately the same intensity to the analyzer. . As usual, the sample gas and the standard gas are alternately supplied to the analyzer together with the carrier gas. In order to reduce measurement inaccuracies, the carrier gas inflow during the sample gas measurement and / or the standard gas measurement is adjusted so that as much signal intensity as possible reaches the analyzer. In using a mass spectrometer, this means that the carrier gas is supplied so that the sample gas and the standard gas produce approximately the same number of hits per unit time at the detector of the mass spectrometer. In this case, strength feedback can be performed to adjust the inflow of the carrier gas.

  It is advantageous if the concentration of the sample gas is determined from the measurements made by the analyzer and the results of the measurements are used for adjusting the inflow of the carrier gas in each case. In this embodiment, the measurement result of the analyzer is supplied to the control circuit. Based on that, the inflow of the carrier gas can be adjusted for the sample gas and / or standard gas and for subsequent measurements.

  It is advantageous if the concentration of the sample gas is determined from the concentration measurement before the sample gas enters the analyzer, in particular before entering the open split, and the result of the measurement is used for adjusting the inflow of the carrier gas. This is an alternative or supplement to the adjustments described above.

  In the development of the present invention, the concentration of the sample gas is obtained from the thermal conductivity. Suitable detectors are known and can be integrated relatively easily in a control circuit for adjusting the carrier gas inflow.

  It is advantageous if the open split operates on the co-current principle. This facilitates management of apparatus configuration and flow technical parameters when implementing this method.

  In another concept of the present invention, two or more sample gases can be supplied to the open split, and at this time, the inflow of the carrier gas is adjusted for each sample gas. Thereby, measurements of different sample gases can be compared with each other. Therefore, preparation and installation of a plurality of open splits can be avoided.

  In a development of the invention, the sample gas can be divided into two or more partial gas streams before entering the open split, and this partial gas stream is fed to the open split. Preferably, the sample gas is divided into two or more capillaries. These capillaries run parallel to each other in an open split. The partial gas flow in different capillaries can be influenced in different ways before entering the open split, for example it can be changed physically or chemically. Furthermore, the use of different capillaries is possible.

  Advantageously, at least one partial gas stream is guided through the trap before entering the open split, thereby removing at least part of the components or substances contained in this partial gas stream. For example, a sample gas containing CO2 and N2 can be guided through an Ascarite trap that removes CO2 that becomes an obstacle during N2 measurement. CO2 has an undesirable characteristic that interferes with subsequent N2 measurements due to its long tail. The method according to the invention makes it possible in this case to produce a partial gas stream which does not contain CO2 and which allows a qualitatively valuable measurement of N2.

  In order to make time between two chromatographic peaks (for example for the measurement of the passing standard gas), a delay loop, for example a delay loop in the form of a capillary of appropriate length, is connected in some cases be able to.

  This method analyzes the isotope ratio of light to medium elements. The sample gas is in particular a compound of these elements that can be transferred to the gas phase. For example, H2, CO2, CO, N2, SO2, N2O, NO, SF6, SF3, SO, Cl2, and a rare gas. Compounds of H, C, N, O, S and Cl, particularly H2, CO2, CO and N2 are preferred.

  According to another idea of the present invention, the sample gas and the standard gas are supplied to the analyzer with or without the carrier gas via an open split. Therefore, in this alternative method, the sample gas is supplied via an open split different from the standard gas. Carrier gas can be supplied to both open splits for mixing and dilution.

  The supply of carrier gas to at least one of the two open splits is regulated by dividing the carrier gas stream into a plurality of parallel partial gas streams, one or more of which are selected to open splits It is advantageous if supplied. The partial gas streams reach the open split in parallel with each other or are pre-merged into one carrier gas stream that enters the open loop. By blocking or passing individual partial gas streams, the resulting carrier gas can be adjusted to the desired flow rate.

  Some or all of the parallel partial gas streams are preferably of different scale. This allows a great number of variations when adjusting the resulting carrier gas flow.

  According to another idea of the invention, before the sample gas is supplied to the open split, the sample gas is split into a flow guided to the open split and a flow split from this flow and not supplied to the open split. . Thereby, too much sample gas flow can be reduced to a low flow rate, so that only the desired sample gas flow reaches the open split.

  The device according to the invention is provided with two or more capillaries for the sample gas, and each of these capillaries is provided with a unique drive for movement between the mixing area and the waiting area. It is characterized by being. With this apparatus, multiple samples can be supplied to one or more analyzers or analyzers simultaneously and / or under the same apparatus conditions. Thus, the calibration usually performed before the measurement is performed can be considerably simplified. This is because, in the most advantageous case, the work is performed by one open split. Preferably, a plurality of capillaries are provided in the open split for the standard gas and the sample gas, and in some cases a plurality of capillaries are provided in the open split for different carrier gases.

  Advantageously, the capillary drive is an actuator. In this case, the capillary drive can be controlled by a common central control unit, so that the capillary can be moved with computer assistance, leaving only the necessary capillaries in the mixing area and waiting for unnecessary capillaries in the waiting area. Be made.

  According to another idea of the invention, the waiting area has a larger cross-sectional area than the mixing area. A large cross-sectional area of the waiting area is desirable to accommodate a large number of capillaries. The relatively small cross-sectional area of the mixing zone reduces gas overflow and dead time during mixing. This is because the volume of the mixing region is greatly reduced due to the relatively small cross-sectional area of the mixing region.

  Advantageously, the cross-sectional area of the waiting area is at least twice, preferably at least five times as large as the cross-sectional area of the mixing area. Depending on the number of capillaries and the required space, the cross-sectional ratio can also be significantly increased.

  According to another idea of the invention, the open split has a funnel-shaped area between the mixing area and the waiting area having a substantially conical shape and a cross-sectional area decreasing towards the mixing area. With this shape, the capillary can be moved between the waiting area and the mixing area without any problem. The capillaries are preferably bendable flexibly and can follow the walls in the funnel region.

  It is advantageous if the length of the mixing zone (in the direction of the capillaries) is longer than the width of the mixing zone, in particular 2-3 times longer. Other ratios are possible. Limiting the volume of the mixing zone is important. Furthermore, the capillaries can be arranged at different positions in the mixing region.

  In the development of the present invention, the standby position in the standby area of the capillary for taking out the gas can be made closer to the mixing area than the standby positions of the other capillaries. The capillary for extracting gas is guided to, for example, an isotope mass spectrometer or other analyzer for examining isotope ratios. The waiting position of the capillary for taking out the gas ensures that no substance reaches the capillary for taking out this gas from the other capillaries in the waiting position.

  It is advantageous if the extraction position in the mixing area of the capillary for extracting gas is closer to the waiting area than the mixing position of the other capillaries. Thereby, it is achieved that sufficient mixing of the gases involved, for example sufficient mixing of the sample gas and the carrier gas, can be performed in the best way before the gas enters the capillary for extracting the gas.

  In another idea of the present invention, a capillary tube for taking out gas is connected to a tube having a contracted portion. The reduction location accurately defines the minimum cross-sectional area of the tube that has a large effect on the volumetric flow rate.

  It is advantageous if the capillary for taking out the gas is connected to a tube made of deactivated special steel. Thereby, a broad sense of reaction (chemical reaction, background effect, etc.) between the tube and the gas passing through it is avoided. This is especially true for gases analyzed by conventional isotope ratio measurement methods.

  In a development of the invention, an open split can be arranged in the analyzer, in particular in an isotope mass spectrometer. In conventional measuring devices, the analyzer is connected to one or more peripheral parts. For this purpose, the analyzer is equipped with a suitable interface, for example a connection for one or more open splits. Thus, in the case of known devices, the open split is provided outside the analyzer. This means that the open split is exposed to conditions outside the analyzer, such as changing temperatures. This is also true indoors. With the device according to the invention, an existing open split is provided in the analyzer so that the ambient conditions important for the accuracy of the measurement can be controlled or kept constant. Specifically, the analyzer can comprise a casing, in which one or more open splits are arranged. An interface for connection of sample gas, carrier gas and standard gas is connected to the open split, and this interface is guided into or out of the casing. The interface is in principle a known pipe joint combined with a valve. The valves are preferably individually adjustable, in particular by computer control. The central control unit performs the automatic electronic inflow adjustment described at the beginning.

  It is advantageous if the open split is constructed on a co-current principle, i.e. the gas flows in only from the same direction, and in particular one side of the mixing zone is closed. When using a relatively light carrier gas, the waiting area is located below the mixing area. On the other hand, the reverse arrangement is used for a relatively heavy carrier gas.

  In another idea of the invention, capillaries with different effective flow rates can be provided for at least one of the gases, ie sample gas, carrier gas, standard gas. Different flow rates can be achieved, for example, by capillaries having different cross-sectional areas, specific cross-sectional reductions, different lengths, and the like. By selection or actuation of appropriate capillaries, gas can be properly supplied to the open split at the desired flow rate. Fine adjustment of the flow rate can additionally or alternatively be performed by an electronic control valve.

  An apparatus for supplying a gas to an analyzer, wherein a predetermined gas flow is adjustable in a gas pipe, provided between the supply pipe, at least one subsequent pipe, and the supply pipe and the subsequent pipe A device comprising a plurality of valves, which are connected in parallel to each other, and which can be switched in stages, ie in binary or incremental fashion, is also the subject of the present invention. Thus, the gas flow in the gas pipe is not regulated by more or less powerful operation of one valve. Rather, it is assumed that a single valve can assume a few (preferably two) discontinuous switching states. One open valve can pass a predetermined gas flow, two open valves can pass almost twice as much gas flow, and so on. It is also conceivable to open the valve in stages, for example by closing / quarter opening / half opening / full opening.

  It is advantageous if a specific restriction with an appropriate flow rate is attached to each valve. At each opening of the valve, the gas flow is determined via a restriction. The throttle is additionally provided on the valve or integrated into the valve.

  It is advantageous if the at least two valves have different throttles. Thereby, different gas flow rates can be produced with fewer parallel valves.

  It is advantageous if a plurality of throttles are provided and the flow rates of these throttles differ by the same multiple. The multiple can be 2 or 2.5, for example. In that case, the flow rate is 1/2/4/8... Or 1 / 2.5 / 6.25 / 15.625, etc., without describing units. Similarly, it can be other multiples.

  It is advantageous if the valve can be controlled manually, electrically or electronically. The valve can also be part of the control circuit. In the simplest implementation, the valve is manually pre-adjusted.

  In order to connect the supply pipe and the subsequent pipe, it is advantageous if a parallel pipe without a valve is additionally provided. The parallel pipe extends in parallel with the valve to ensure that a predetermined gas flow always flows. This gas flow preferably meets the minimum flow requirements of the attached open split.

  In another aspect of the invention, the apparatus is characterized by having an open split after the subsequent tube for mixing the gas flow with the other gas flow. The gas flow reaching the open split is regulated by a valve.

  In the present invention, a subsequent second pipe can be provided, in which a plurality of valves are arranged in parallel between the subsequent second pipe and the supply pipe. Therefore, this supply pipe supplies gas to the subsequent two pipes, and these pipes are each provided with a separate valve group in order to regulate the respective gas flows.

  It is advantageous if each of the valves for the subsequent second pipes is provided with a specific restriction with an appropriate flow rate.

  In another idea of the invention, the subsequent second pipe is provided with a unique open split, ie a second open split. Thus, the gas flow can be divided into two different open splits.

  It is advantageous if a mass spectrometer is arranged as an analyzer after one or two open splits. This mass spectrometer is in particular an isotope mass spectrometer, a mass spectrometer with a plasma source (ICP-MS), a mass spectrometer that performs collision gas control for collision cells and reaction cells. The apparatus according to the invention preferably regulates or controls the carrier gas flow or collision gas flow leading to the analyzer or analysis device.

  In the present invention, the supply pipe can be provided with a branch for bypassing the valve and supplying directly to the open split. Since this bifurcation has no restriction or only a relatively small restriction, in other cases a gas flow equal to or greater than the gas flow through the largest restriction is possible.

  In another aspect of the present invention, the open split or one of the plurality of open splits includes a first capillary for supplying a high flow rate gas and a second capillary for supplying a lower flow rate gas. Yes. Preferably, different concentrations of sample gas are supplied via the first and second capillaries, while the carrier gas reaches into the open split via the other subsequent tubes connected to the next capillary.

  In the present invention, the open split may comprise a capillary for extracting gas, i.e. a degassing capillary, which is arranged in a cocurrent manner with respect to the first or second capillary, and each It is arranged countercurrent to the other capillary, i.e. the second or first capillary. Preferably, a second capillary for supplying gas with a low flow rate is arranged in a countercurrent manner with respect to the degassing capillary. Correspondingly, the first capillary, i.e. the capillary for supplying the gas with a high flow rate, is arranged in a cocurrent manner with respect to the degassing capillary.

  In another idea of the invention, the venting capillary has an outer diameter that is smaller than the inner diameter of the second capillary for supplying the gas. In addition, the venting capillary and the second capillary are relatively movable and coaxial with each other such that in some locations the venting tube is inserted into the second capillary and in other locations the capillaries are separated from each other. Be placed.

  In another aspect of the invention, the open split or one of the plurality of open splits includes a capillary for supplying gas. In this case, the capillary has a branching portion that can be closed via a valve. This valve preferably has the function of reducing the flow rate or gas flow through the capillary. Since the partial gas flow flows from the branch when the valve is opened, only the appropriate partial gas flow reaches the open split via the capillary.

  In another aspect of the invention, the open split or one of the plurality of open splits includes a capillary for supplying gas, wherein two or more supply pipes communicate with the capillary. This allows different gases or gas samples to be supplied to the capillaries.

  In the present invention, the supply pipe can be provided with a multi-way valve, and this multi-way valve can pass the gas toward the open split at one switching position and discharge the gas at the other switching position. This multi-way valve is preferably a three-way valve. This three-way valve directs the gas towards the open split or for other purposes. Thereby, a constant pressure ratio can be achieved in a range provided in front of the supply pipe, that is, in the so-called peripheral part.

In another idea of the present invention, the carrier gas can be supplied to two different open splits via a supply pipe, and the sample gas can be supplied to one open split via a capillary tube. Can be supplied to other open splits via capillaries, and the degassing capillaries are guided from both open splits to the analyzer.
a) The first capillary for the carrier gas is guided to the open split,
b) The second capillary for the low flow sample gas is guided to the open split,
c) A third capillary for a sample gas having a higher flow rate is guided to the open split,
d) An apparatus for supplying a sample gas and a carrier gas to the analyzer, characterized in that the fourth capillary is guided from the open split to the analyzer as a degassing pipe, is also an object of the present invention.

  Accordingly, the so-called low flow rate sample gas and high flow rate sample gas pass through the same open split and reach the analyzer.

  Advantageously, a carrier gas supply pipe having a branching part is arranged in front of the first capillary, the branching part being connected to a second capillary for a low-flow sample gas. A valve can be provided at the branch. This valve blocks or passes the gas flow in the branch.

  The fourth capillary can be advantageously inserted into the second capillary for the low-flow sample gas as a degassing tube. Thereby, a low flow rate of sample gas is sent directly to the venting capillary.

  Other features of the invention will be apparent from the claims and others from the description. Next, advantageous embodiments of the present invention will be described in detail with reference to the drawings.

  To illustrate the method according to the invention, reference is first made to FIG. The cooperation of the individual components when analyzing the isotope ratio of the sample burned in the reactor 20 is shown. The gaseous combustion products are guided through the gas chromatograph 21 and exit from this gas chromatograph as sample gas.

  The sample gas flows to the ion source 23 via at least one open split 22. The ions formed there reach the detection system 25 via the direction changing unit 24. This detection system 25 preferably comprises a number of detectors.

  The purpose of the analysis is to measure the isotope ratio of the sample gas. For this purpose, the sample gas is continuously supplied to the open split 22 alternately with the standard gas from the standard gas source 26. In addition, the carrier gas from the carrier gas source 27 can be supplied to the open split 22.

  In order to simplify the illustration, only one sample supply unit 28, carrier gas supply unit 29, and standard gas supply unit 30 are shown in FIG. In practice, a plurality of supply pipes and supply sources can be provided.

  Each gas reaches the open split 22 via a plurality of capillaries, ie, a sample gas capillary 31, a carrier gas capillary 32 and a standard gas capillary 33. In addition, a capillary tube 34 communicating with the ion source 23 is provided. This capillary is also called a degassing tube. Again, a plurality of capillaries can be provided, depending on the existing supply tubes.

  The capillaries 31-34 can be moved, i.e. put into the open split or returned again by known actuators 35-38 not shown in detail. Furthermore, valves 39 to 42 that can electronically control the capillaries 31 to 34 can be provided. Because of the danger of separation, the capillary tube 34 (which leads to the analyzer) is operated with as few valves as possible.

  Here, the open split 22, the ion source 23, the direction changing unit 24, and the detection system 25 including the capillaries 31 to 34, the actuators 35 to 38, and the valves 39 to 42 are integrated into an isotope mass spectrometer 43 as an analyzer. At the same time as a component of the same device unit surrounded by the casing 44 as much as possible.

  The mass spectrometer 43 is provided with an electronic control device, here a computer 45 having an interface for transmitting data. The computer 45 can be integrated with the mass spectrometer 43 or connected to the mass spectrometer (as shown in FIG. 1). Conductive or data lines and / or control lines shown in broken lines connect computer 45 to at least detection system 25, actuators 35-38, and controllable valves 39-42.

  Between the gas chromatograph 21 and the sample gas supply unit 28, for example, a detector 46 of the concentration of the sample gas is preferably provided in order to detect the thermal conductivity. The detector 46 is similarly connected to the computer 45 via a data line.

  Various gas supplies 28, 29, 30 can be connected to the mass spectrometer 43 via suitable interfaces, such as joints 47, 48, 49.

  Various gas flows are adjusted by the computer 45 when measuring the isotope ratio. For this purpose, the valves 39 to 42 are adjusted and / or the actuators 35 to 38 for moving the capillaries 31 to 34 are controlled. Furthermore, the adjustment can be influenced by the measurement result, in particular the analysis result of the detection system 25 and / or the concentration measurement of the detector 46.

  Various examples of the measurement process will be described based on other figures.

  In FIG. 2, the material is converted in the reactor 20. For example, CO2 and N2 are generated from this substance. These gases are temporarily separated from each other in the gas chromatograph 21 and reach a mass spectrometer (not shown) via a sample gas supply unit 28.

  Based on the signal from the detector 46, it is possible to confirm the generation of CO2 substantially larger than N2. This can be taken into account by dilution with a carrier gas in the open split range.

  However, CO2 is a source of measurement technical problems, particularly in the context of isotope ratio measurements. The sample gas is measured alternately with the standard gas, so that CO2 is also measured alternately. Since this CO2 has a chromatographic peak with a long tail, the measurement of N2 in subsequent measurements is disturbed. Furthermore, CO is formed from CO2 in the ion source of the mass spectrometer. This CO has the same mass: charge ratio as N2.

  In order to solve the above problem, the sample gas supply unit 28 is divided into two supply pipes 51 and 52 via a divider 50 as shown in FIG. A trap 53 is incorporated in the supply pipe 51. This trap is here formed as an ascarite trap to keep CO2. Therefore, only N2 reaches the open split via the supply pipe 51. On the other hand, the same gas as the sample gas supply unit 28 flows from the pipe 52. Of course, other treatments of the sample gas stream are possible.

  The supply pipes 51 and 52 are each connected to the open split via a unique joint, valve and capillary. This connection is made in a manner similar to that of FIG. 1 and as shown, for example, in the range of Periphery A in FIG. When measuring the isotope ratio, the structure of FIG. 3 can be used so that N2 and CO2 flow from the same sample through the same open split in the measurement process. At that time, in the mass spectrometer, the gas flowing through the supply pipe 52 can be diluted within the range of the open split so that there is always an ideal signal intensity in the measurement technique. The concentration is calculated and adapted based on the signal supplied from the detector 46. This method of concentration monitoring and adaptation by dilution can also be carried out with the embodiment of FIG.

  FIG. 4 shows an apparatus according to the present invention having an open split 22 as a component of the mass spectrometer 43. Here, gas is supplied to the open split 22 from a number of capillaries. The capillary is provided with a number of actuators (not shown) and valves. For the sake of clarity, the other components of the mass spectrometer and the electronic control computer 45 with associated data lines are not shown.

  By way of example, four standard gas capillaries 54-57, two carrier gas capillaries 58, 59 and three sample gas capillaries 60, 61 and 62 and a capillary 63 leading to a mass spectrometer are provided. The above reference numbers are also described in FIGS.

  Here, the peripheral portion A is understood to be a unit for sample preparation. This unit is, for example, a unit as shown in FIGS. 1 to 3 and includes two supply pipes 51 and 52 as can be seen from FIG. Similarly, the peripheral part B shows another unit for sample preparation, and this unit corresponds, for example, to FIGS. That is, like the sample gas supply unit 28, only one supply pipe 64 is provided.

  There is a feature within the capillaries 63 leading to the ion source. That is, the contraction location 65 is provided. The capillaries 63 are made of inactivated special steel and have a strictly defined cross-sectional area that is narrowed in the area of the shrinkage point 65. This creates a reproducible condition for this capillary. A shut-off valve 66 is disposed after the reduction portion 65, similar to the valve 42 of FIG.

  The open split 22 is configured according to the parallel flow principle. See especially FIG. That is, the capillaries are inserted into the open split in parallel with each other from the same direction, and the sample gas, standard gas and carrier gas accordingly flow into the open split from the same direction.

  The open split 22 includes a mixing area 67, a waiting area 68, and a transition area 69 between them. The mixing area 67 is closed on one side and has a smaller cross-sectional area than the waiting area 68. The ratio of the cross-sectional areas to each other depends on the required space of the capillaries within the waiting area. In order to be able to achieve as fast a gas exchange as possible for the alternately supplied gas, the smallest possible cross-sectional area of the mixing zone 67 is desired.

  The mixing area 67 is provided with at least two different positions. That is, an outer mixing position 70 for the capillary 63 leading to the ion source is provided as an extraction position for this capillary, and an inner mixing position 71 for the other capillaries. In this context, the terms “inside” and “outside” relate to the spacing of both mixing positions 70, 71 up to the open split inlet area 72. The mixing position 70 close to the inlet area 72 is called the outer mixing position. This is because this mixing position is closer to the only opening of the open split than the inner mixing position 71. The take-out position of the capillary 63 may be provided slightly outside the mixing area 67 instead of on the mixing area boundary as shown in the figure.

  The waiting area 68 similarly has two waiting positions, an outer waiting position 73 for all capillaries except the capillary 63 and an inner waiting position 74 for the capillary 63. For example, see FIG.

  The transition region 69 is conically shaped and has its minimum cross section in the transition range to the mixing region 67 and its maximum cross section in the transition range to the standby region 68. Each of the mixing area 67 and the waiting area 68 itself is formed to have a constant cross section over its length. Different implementations are possible. It is important to insert the capillary into the mixing region 67 easily and reproducibly.

  In the form of this embodiment, an open split 22 having a downward inlet area 72 is provided, which makes it particularly suitable for use with a light carrier gas (compared to air). This gas collects in the mixing area 67 and pushes away the heavy gas.

  In FIG. 5a, only the carrier gas capillary 59 is active. This means that only this capillary has reached the mixing zone 67. The carrier gas exiting the capillary 59 pushes all other gases away from the mixing zone 67. Gas exiting the other capillaries does not reach the capillaries 63. This is because the capillary protrudes deeper into the open split at its standby position 74 than any other capillary that is not operating.

  In the illustration of FIG. 5b, the carrier gas capillary 59, the standard gas capillary 4 and the capillary 63 leading to the ion source are activated. Thereby, the standard gas diluted with the carrier gas is guided to the ion source.

  FIGS. 6 a, 6 b and 6 c show the insertion of one or more carrier gas capillaries into the working volume of the mixing region 67. The arrangement of FIG. 6c with two carrier gas capillaries can be combined with activated sample gas capillaries 60-62, for example to strongly dilute very high sample concentrations (FIG. 6c, capillaries 60-62). Are not working).

  The introduction of the carrier gas into the mixing region 67 serves to rapidly push out a gas having a strong absorption such as SO2 so that an experiment with a low background can be performed subsequently. FIG. 6d shows the change over time of the signal of the detector in the case of the arrangement according to any one of FIGS. First, a strong background signal is observed. See curve section 75. After a short time, the background signal fades rapidly or is very weak. See curve section 76.

  7a-7d have standard gas signal with carrier gas (capillary 57, 59, 63), sample signal with other carrier gas (capillary 60, 58, 63), and carrier gas used first. Fig. 6 shows alternating measurements of other standard gas signals (capillaries 59, 56 and 63). From FIG. 7d, different signal intensities and sample signals (both in the middle) can be seen. The first (large sample signal) is followed by the standard gas signal of the capillary 57 with almost the same intensity, while the (weak) sample signal is followed by the standard gas (also weak) signal from the capillary 56. ing. Different standard gas signal intensities are adjusted by different flow rates as a characteristic of the capillaries 56, 57 or by an electronic valve attached respectively. This valve is shown only in FIGS. Both of these methods of dilution adjustment can be combined with each other.

  Figures 8a-8e show the signal strength during various capillary actuations and measurements of two sample flows in one perimeter. At that time, the sample gas capillaries 60 and 61 are sequentially operated. Here, standard gas pulses that are variously diluted with a carrier gas are located on both sides of the sample signal. See the first and last square signals in FIG. 8e. The sample gas is not diluted in the open split. Accordingly, FIGS. 8b and 8c do not show the activated carrier gas capillary. All signals are analyzed within one measurement sequence. This is also true for the other measurements shown.

  In the case of the example of FIGS. 9a to 9e, both sample flows in the peripheral part A are switched in the measurement sequence as in the above-described FIGS. 8a to 8e. See both peaks in the middle of FIG. 9e. Here, however, the sample gas is diluted by the carrier gas from the capillary 58 in the open split. The intensity of the second sample signal is relatively weak. Accordingly, the strength of the standard gas from the capillary 56 is adapted.

  Figures 10a to 10e show a measurement-sequence for measuring two sample flows from both perimeters A, B. Each standard gas is detected before both sample signals. In this case, the standard gas from the capillary 57 is diluted with the carrier gas from the capillary 59 (before the first sample signal), and the standard gas from the capillary 56 is again diluted with the carrier gas from the capillary 59. In order to adjust the different sample concentrations of the ambient gas to the optimum range for the analyzer, the carrier gas is added in different amounts each time. Therefore, both peripheral signals can be set to substantially the same intensity.

  FIGS. 11 a-11 e show three consecutive sample signals from the same sample capillary 60. On the one hand, the dilution from an arbitrary capillary is constant (FIG. 11a), and on the other hand, the dilution is different each time in order to obtain the same signal intensity at the detector (see FIGS. 11b to 11e). The arrangement of FIG. 11 b shows strong dilution from the carrier gas capillary 58. A simple dilution from the carrier gas capillary 59 is shown in FIG. 11c. In the arrangement of FIG. 11d, no dilution is performed. Different strength dilutions result in the same signal strength shown in FIG. 11e. Otherwise, the different signal strengths shown in FIG. 11a are expected. Here, the standard gas pulses which are also present are not shown for the sake of clarity. As in other measurement-sequences, after each sample and standard measurement, the analyzer automatically changes the gas arrangement, eg changing the magnetic field strength of the redirecting unit or changing the ion source parameters. Done.

  There are many advantages to adjusting the concentrations of the standard and sample gases to computer controlled or electronically controlled by increasing or decreasing the carrier gas flow.

  Standard gas consumption is much lower than before. This is because, generally after the preload adjustment, no other control is necessary, and therefore a conventional bleeder capillary is no longer needed in other cases to bleed the decompressor. This reduces operating costs, maintenance costs, standard gas calibration costs, and hazards when using toxic or combustible standard gases.

  Accurate sample measurement and sample knowledge for signal intensity control is no longer necessary. This is because the signal strength of the standard and the sample can be automatically adapted to each other by computer control. For example, the intensity of the standard gas pulse can be adjusted depending on the sample to be measured by controlling the dilution within the open split to achieve optimal measurement accuracy. Furthermore, when the peripheral part connected in front has a preliminary analysis unit such as a flame ionization detector (FID) or a thermal conductivity detector (TCD), the concentration adjustment of the sample in the gas is optimal in real time. Is possible. The sample concentration can be estimated from the result of this detector. To obtain the highest measurement accuracy, the sample can be optimally diluted by computer control in an open split.

  Instrument diagnostic measurements such as linearity tests or often performed H3-factor measurements can be similarly automated by computer control. Since the experimenter no longer needs to be present and the calibration factor determination can be performed in conjunction with the measurement, the accuracy of the experiment is further increased.

  Complex measurement procedures that assume changes in the mixing ratio of the standard gas or sample gas in the open split can now be automatically performed as a programmable sequence without intervening in between. Thereby, the utilization of the measuring capability of the device is further enhanced.

  It is very advantageous to electronically control one or more carrier gases in connection with the open split shown. This is because open split greatly expands the possibilities of automated measurement sequences.

  In the case where a number of identical sample signals are consecutive, the drift caused by the situation can be accommodated by automatic dilution adjustment.

  Detection of the sample peak before the standard signal is advantageous when the retention time of the sample peak is not accurately known from the periphery. In this situation, the intensity of the standard signal to be recorded following the sample peak can be optimally adjusted in real time.

  Concentration control by adjusting dilution does not cause fractionation.

  The device has the following advantages. The supply pipe between the open split and the analyzer is no longer arranged outside the analyzer between the periphery and the analyzer, but in the analyzer. Thus, the capillaries can be well protected against temperature changes and other disturbing effects. Signal stability is improved and this is accompanied by an increase in measurement accuracy. This effect is further enhanced by the use of an inactivated steel capillary with a Krimprestriction for the supply tube leading to the analyzer.

  When many peripheral parts are connected, the cost is reduced. This is because only one open split is required per analyzer as an interface, and it is not necessary to provide one interface for each peripheral portion as described above.

  Since one open split may be cleaned with the carrier gas, the consumption of the carrier gas and the associated costs are reduced.

  Compared to conventional analyzer design, fewer shut-off valves are required and leakage is less likely, reducing maintenance work and costs.

  A relatively large number of peripheries can be connected to the analyzer or open split simultaneously. The waiting area 68 provides sufficient space for the increased number of capillaries.

  From the periphery where the sample gas is divided, different sample gas streams can be supplied to the open split and thus to the analyzer via different capillaries as required.

  Switching between standard gases or between peripherals or between different peripheral supply pipes is very simple. This is because the process is determined only by the computer controlled capillary position within the open split.

  Peripheral installation or switching between peripheries is possible without supplying air into the analyzer and therefore with minimal dead time and start-up time.

  Automatic switching between connected standard gases, between perimeters or between different perimeter supply pipes increases analyzer utilization and allows for economical operation. This is because an automatic measurement sequence including different peripheral parts and peripheral branch parts is possible without manual intervention.

  For applications such as air analysis applications, it is advantageous if multiple standard gases can be supplied to the mass spectrometer simultaneously. Thereby, the interference effects of different isotopes can be examined and calibrated. In addition, multi-component mass calibration of the analyzer can be performed when different gases such as CO2, SO2, and heavy components such as methyl chloride and other components are included. This allows for greatly improved analyzer mass calibration. This is because the mass calibration of the analyzer defined via a number of points, and hence higher measurement accuracy is achieved.

  In the case of a peripheral with high background and / or drift in sample preparation, it is also advisable to put the peripheral background gas together in the analyzer when measuring the standard gas signal. In the case of conventional techniques, this is done via a separate feed tube with an open split reserved for the sample. In the case of the embodiment according to the invention, this can be achieved by actuation of a capillary leading to a carrier gas capillary, a sample gas capillary, a standard gas capillary and an analyzer. Thereby, the standard gas flow can be reduced to 1/5 or less. Thereby, the life of the standard gas container is extended five times or more, and the cost and work involved in replacement are reduced.

  When multiple carrier gas supply pipes with different inflow rates are installed, the concentration of the standard gas and sample gas can be adapted to the optimum measurement procedure within a certain limit and without separation within the range of the measurement routine. . See, for example, FIGS.

  The waiting position 74 for the capillary 63 leading to the analyzer is deeper than the waiting position 73 of the other capillary in the open split. Thereby, in a stopped arrangement (see FIG. 5a), only the carrier gas reaches the analyzer and no gas from other waiting supply capillaries.

  The mixing volume that is kept to a minimum by the reduced diameter of the mixing zone 67 results in short gas switching times and optimal mixing conditions.

  A carrier gas having a density smaller than the density of the surrounding air is 180 degrees in the direction of air intrusion into the interface and associated obstructions at the open slit with the open end facing downward (as shown). Prevent more effectively than rotating. An open split rotated 180 degrees in direction is advantageous for the use of a carrier gas having a density greater than air. In this case, the device shown on the figure is rotated 180 degrees.

  All tubes or capillaries entering and leaving the open split are flushed with a suitable operating gas at all times, i.e. even in standby mode. Therefore, when newly used, failure due to impurities such as water and air does not occur, and the start-up time and dead time are greatly shortened.

  The device according to the invention, in particular the open split, offers a myriad of possible capillary arrangements and a myriad of switching sequences for a wide variety of analytical problems. The arrangement order shown on the basis of the figures can be arbitrarily combined for a number of applications and is not nearly perfect.

  FIG. 12 shows the principle of regulation of the gas flow in the pipe by means of valves parallel to each other. As an example, a supply pipe 80 for helium as a carrier gas is divided into eight branch pipes 81 to 88. Each branch pipe 81-88 has its own valves 89-96. The valve is preferably electrically switchable between two switching positions, namely an open position and a closed position. Restrictions not shown in FIG. 12, for example, predetermined cross-sectional contractions of the branch pipes 81 to 88 are attached to the valves 89 to 96. Thereby, the flow rates in the individual branch pipes are different. Here, the flow rate is, for example, 1% / 2% / 2% / 5% / 10% / 20% / 20% / 40% of the flow rate of the supply pipe 80. By opening the individual valves 89-96, it can be adjusted to almost any value between 1% and 100%. Following valves 89-96, tributary tubes 81-88 are again assembled into a subsequent tube 97 having a resulting flow rate.

  A backflush pipe 98 having an inherent valve 99 is provided in parallel with the branch pipes 81 to 88. Through this backflush tube, the pressure can be reduced in the area of the subsequent tube 97. The tube 97 is, for example, a part of a capillary tube that communicates with an open plate, as will be described in detail with reference to FIG.

  Two open splits 100 and 101 can be confirmed as gas supply devices to be analyzed that reach the mass spectrometer MS. The open split 100 is for supplying sample gas, and the open split 101 is for supplying five different standard gases in this case. Dividing into a separate sample gas supply and standard gas supply has the advantage that very little sample flow can be measured well. The sample stream may enter directly into the open split 100, or the sample stream may be mixed with the carrier gas in a relatively small mixing area within the open split. A separate feed is also advantageous because the standard gas can be measured easily and reliably “relative to the sample gas background”.

  Here, in order to supply the standard gas, five supply pipes 102 to 106 are provided. Through this supply pipe, for example, H2, N2, SO2, CO and / or CO2 can be supplied to the open split 101 as a standard gas. The three supply tubes 102-104 lead to a common capillary 107, which can be moved into or out of the open split 101 via an actuator. The other supply pipes 105, 106 lead to a common capillary 108, which can be moved in the axial direction by an actuator in the same manner as the capillary 107.

  Each of the supply pipes 102 to 106 includes a manual control valve 109, a predetermined throttle 110, and an electric switching valve 111. The standard gas (s) that are activated each time are preselected via valves 109 or 111 and move up the capillaries 107 or 108 to the mixing region 112 of the open split 101. The capillaries 107 and 108 shown in FIG. 13 are in a standby position outside the mixing area.

  The above structure allows two or more standard gases to be alternately supplied in equilibrium, optionally after (gas) chromatography, e.g. when analyzing two or more elements in a sample. . On the other hand, many or almost any number of standard gases can be automated and prepared with minimal cost.

  The carrier gas, in this example helium, enters the open split 101 via the capillary 113. For this purpose, a valve device is provided as shown in FIG. The capillary tube 113 has the function of the subsequent tube 97 of FIG. In FIG. 13, the carrier gas supply unit is formed so that the minimum carrier gas always reaches the open split 101. Thereby, this open split is always sealed against the surroundings.

  The sample gas is supplied differently according to the flow rate determined by the peripheral part (not shown). A high flow rate (HF) sample is guided through the capillary 114 into the mixing region 115 of the open split 100. Here, two supply pipes 116 and 117 for the high flow rate sample are shown. Both supply pipes lead to the capillary 114 and can be switched via a switching valve 118.

  The low flow (LF) sample enters the open split 100 from the opposite side (opposite the capillary 114). A capillary 119 (degassing tube) reaching from the open split 100 to the mass spectrometer MS can be moved between two positions by an actuator, ie between the mixing region 115 and the low flow sample capillary 120.

  The capillary 119 (gas vent tube) is matched to the diameter of the capillary 120 and can be inserted into the capillary 120 (as shown in FIG. 13). Thus, substantially all of the sample gas stream reaches the mass spectrometer. This is advantageous when the sample flow rate is very low.

  When the capillary 119 is not inserted into the capillary 120 and is moving into the mixing region 50, the sample gas flowing into the open split countercurrently from the capillary 120 is usually diluted with a carrier gas. The carrier gas is supplied from the supply pipe 80. However, in FIG. 13, the capillary 115 is inserted into the capillary 120 as described above.

  When the peripheral part for preparing the low flow rate sample gas is not provided, the carrier gas is supplied through the capillary 120 by connecting the branch part 121 of the supply pipe 80 to the capillary 120 instead. I can.

  For example, when measuring a high flow rate sample, the excess low flow rate sample can be discharged from the capillary 120 via the air vent valve 122.

  Depending on the position of the valve 118, the high flow rate sample reaches the open split 100 via the capillary 114. Here, since the valve 118 is formed as a three-way valve, an unnecessary high flow rate sample flow can be shut off and discharged (bleed out) each time. Thereby, the gas flow is always constant in the peripheral part (not shown) arranged in front. Accordingly, measurement failures due to diffusion are avoided.

  After the supply tubes 116, 117 join the capillary 114, the capillary has an air vent branch 123. This air vent branch includes a unique valve 124. The gas flow reaching the capillary 114 can be partially exhausted from the air vent branch 123 by appropriate switching of the valve 124 such that the reduced gas flow reaches the open split 100.

  In the mixing zone 115, the sample gas stream is diluted by the carrier gas stream and reaches the mass spectrometer via the capillary 119. Other suitable detectors may be provided in place of the mass spectrometer.

  The dilution of the sample gas stream is controlled by adjusting the carrier gas stream. The carrier gas flow reaches the open split 100 through the capillary 125. Between the supply tube 80 and the capillary tube 125, a plurality of valves 126, here three valves 126, are arranged in parallel to each other. Subsequent to this valve, variously formed throttles 127, 128, 129 are provided. A wide variety of carrier gas flows can be regulated in the capillary 125 by selection of individual valves 126 or combinations thereof. Continuous supply from the supply tube 80 to the capillary tube 125 is not necessary. This is because in many cases the high flow periphery already contains a basic flow or individual carrier gas. Due to the computer control of the valve 126, there is always sufficient flow in the open split 100 so that no ambient gas can enter.

  In the present example, five valves 127 are arranged in parallel between the supply tube 80 and the capillary tube 113. The valve 127 can be electrically switched similarly to the valve 123. Each valve 127 is provided with a specific throttle 131-135. Further, a pipe 136 having no valve is provided in parallel with the valve 130. The basic flow of carrier gas always flows into the open split 101 through this pipe 136. This tube 136 also has a specific restriction 137.

  The restrictors 131 to 135 (similar to the restrictors 127 to 129) are, for example, as shown in FIG. 12 or in binary steps, that is, at a flow rate of 2 times (1 times, 2 times, 4 times, 8 times, etc.) It is formed in stages. At that time, the flow rate doubles from throttle to throttle. Alternatively, a larger multiple, for example 2.5, can be used, in which case the flow rate is 1 / 2.5 / 6.25 / 15.625, etc. The larger the multiple, the fewer valves required for the high dynamic range and the greater the step width. Changing the standard gas or sample gas to the desired dilution by appropriate control of the valves 126, 130 is performed by a computer-controlled control unit. This control unit adjusts the dilution step that is most easily achieved each time.

  In order to keep the inflow pressure (periphery) constant, a certain minimum flow is required. For this purpose, an essential minimum supply is provided from a pipe 136 provided with a restriction 137. Instead, only incidental conditions may be provided in the switching control. For this incidental condition, at least one of the valves 130 or 126 must be opened or an additional air vent is provided. In some cases, this air vent is only used when all flow in the direction of the intended flow is blocked.

  All throttles connected to the supply pipe 80 are preferably harmonized with one another. For example, the throttles 129/128/127/131/132/133/134/135 and 137 have flow rates of 7/2/1/35/16/5/2/1 and 2.

  Although the valve 99 already described based on FIG. 12 is not shown in FIG. 13, it can also be provided in FIG. This valve can be used when a very quick adjustment is desired, when the pressure is to be reduced rapidly, or when the subsequent tube 97 is connected to a system that is closed early to generate back pressure. Also works as.

  The apertures 110, 127-129 and 131-137 described above can be implemented in various ways, for example with the same capillaries of different lengths, different openings in the flow diaphragm, specific cross sections, etc.

  The above control of the gas flow for the carrier gas is very advantageous when the valve 126 or 130 or 89-96 is once set as prescribed and control by feedback is no longer performed. The desired flow rate is achieved practically immediately. The measurement is not disturbed by the re-control process. Furthermore, the amount of waste (Tovolumina) is smaller than that of the conventional flow rate regulator. It can be easily constructed from known simple parts and inert materials. The use of a flow regulator formed by valves 89-96, 126 and 130 in a binary or progressive manner is very advantageous, especially in the context of open splits. This is because here the preload (by means of a normal mechanical pressure regulator in the carrier gas supply) and the target pressure (by exposing the open split to ambient / atmosphere) are constant.

  The above binary or gradual flow rate adjustment by parallel valves can be performed by various devices and methods. That is, the above flow rate adjustment is possible not only for diluting the sample and standard gas in isotope mass spectrometry but also for adjusting the carrier gas for ICP-MS, the collision gas of the collision cell and the reaction cell, etc. is there.

  The air vent valve 122 and / or the valve 124 in the air vent branch 123 can be switched by computer control, and can be operated in harmony with the rest described with reference to FIG.

1 is a schematic illustration of an apparatus for carrying out the method according to the invention, comprising a reactor, a gas chromatograph, an open split, an ion source, a direction changing unit, a detector and an electronic control device. FIG. 2 shows a portion of FIG. 1, namely a reactor, a gas chromatograph and a detector for thermal conductivity. Fig. 3 shows a part of Fig. 2 with a dividing part for sample supply. Shows an open split integrated into a mass spectrometer, which has two perimeters connected to it, which generates a total of three different sample gas streams, and the open split is a standard gas With four capillaries for the carrier gas and two capillaries for the carrier gas. Two different states of the open split, that is, an off state and a state in which a standard gas diluted with a carrier gas is sent to the mass spectrometer are shown. 5a and 5b show three different states of an open split, i.e. one of the two carrier gas capillaries activated or both of the carrier gas capillaries actuated, whereby the subsequent back In order to be able to perform ground-poor experiments, highly absorbing gases that may be present are excluded from the mixing region. The three states of the open split of FIGS. 5a and 5b are shown, with signals for two standard gas pulses and two sample gas pulses simultaneously. Four different states of the open split are shown, and the signal intensities for two standard gas pulses and two sample gas pulses are shown simultaneously. The signal strengths of two standard gas pulses and two sample gas pulses are shown, and four states of open split are shown. The signal strengths of two standard gas pulses and two sample gas pulses are shown, and four states of open split are shown. The signal intensity of the sample gas pulse when the dilution is constant and when the dilution changes is shown, and the three states of the open split in FIG. 5 are shown. 1 is a schematic illustration of the control or regulation of gas flow by valves parallel to one another. Figure 2 shows a combination of two open splits for supplying a low flow sample gas, a high flow sample gas, a carrier gas (with different gas flows) and a standard gas to a mass spectrometer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Reactor 21 Gas chromatograph 22 Open split 23 Ion source 24 Direction conversion unit 25 Detection system 26 Standard gas source 27 Carrier gas source 28 Sample gas supply part 29 Carrier gas supply part 30 Standard gas supply part 31 Sample gas capillary 32 Carrier gas capillary 33 Standard gas capillary 34 Capillary leading to the ion source 35 Actuator 36 Actuator 37 Actuator 38 Actuator 39 Valve 40 Valve 41 Valve 42 Valve 43 Isotope mass spectrometer 44 Casing 45 Electric control computer 46 Detector 47 Joint 48 Joint 49 Joint 50 Division Instrument 51 Supply pipe 52 Supply pipe 53 Trap 54 Standard gas capillary 55 Standard gas capillary 56 Standard gas capillary 57 Standard gas capillary 58 Carrier gas capillary 59 Carrier gas capillary 60 Sample gas Capillary 61 Sample gas capillary 62 Sample gas capillary 63 Capillary tube leading to the ion source 64 Supply tube 65 Contraction point 66 Shut-off valve 67 Mixing region 68 Standby region 69 Transition region 70 Outer mixing position 71 Inner mixing position 72 Inlet range 73 Outer standby Position 74 Inside standby position 75 Curve branch 76 Curve branch 80 Supply pipe 81 Branch pipe 82 Branch pipe 83 Branch pipe 84 Branch pipe 85 Branch pipe 86 Branch pipe 87 Branch pipe 88 Branch pipe 89 Valve 80 Valve 91 Valve 92 Valve 93 Valve 94 Valve 95 Valve 96 Valve 97 Subsequent pipe 98 Backflush pipe 99 Valve 100 Open split 101 Open split 102 Supply pipe 103 Supply pipe 104 Supply pipe 105 Supply pipe 106 Supply pipe 107 Capillary 108 Capillary 109 Manual control valve 110 Throttle 111 Electric valve 112 mixture Area 113 Capillary 114 Capillary 115 Mixing area 116 Supply pipe 117 Supply pipe 118 Switching valve 119 Capillary (gas vent pipe)
120 Capillary (low flow)
121 Branch portion 122 Air vent valve 123 Air vent branch portion 124 Valve 125 Capillary 126 Valve 127 Throttle 128 Throttle 129 Throttle 130 Valve 131 Throttle 132 Throttle 133 Throttle 134 Throttle 134 Throttle 135 Throttle 136 Pipe 137 Throttle

Claims (63)

-Supplying sample gas and / or standard gas to at least one analyzer via at least one open split;
-Adding a carrier gas to the sample gas and / or standard gas via the at least one open split;
-Changing the supply of the carrier gas to the sample gas and / or standard gas to adjust the concentration of the sample gas and / or standard gas;
Use a control unit for adjusting the concentration of the sample gas and / or standard gas by adjusting the carrier gas supply;
A method for analyzing isotope ratios.   The carrier gas supply is changed in stages, whereby parallel carrier gas split flows of the same or different scale can be actuated and combined with each other, and the resulting single carrier gas flow can be adjusted. The method according to claim 1.   An open split (22) for at least one gas, ie at least one of sample gas, carrier gas, standard gas, is provided with capillaries (31-33, 54-62) having different effective flow rates. 3. A method according to claim 1 or 2, wherein the gas flow is adjusted by selecting and actuating a capillary having a desired flow rate.   An open split for at least one of the gases, ie sample gas, carrier gas, standard gas, comprises capillaries (31-33, 54-62) having different cross-sectional areas; 3. A method according to claim 1 or 2, wherein the gas flow is adjusted by selecting and actuating capillaries having a desired cross-sectional area.   5. The method according to claim 1, wherein only the inflow of the carrier gas is adjusted in each case and the remaining gas flow is left unregulated.   The carrier gas inflow is adjusted each time so that the concentration of the sample gas and / or the standard gas remains substantially constant at least in the measurement range optimum for the analyzer. The method according to any one of claims 2 to 5.   2. The inflow of each carrier gas is adjusted during alternately successive measurements so that the sample gas and the standard gas provide a signal having substantially the same intensity to the analyzer. The method as described in any one of 2-6.   The concentration of the sample gas is obtained from the measurement performed by the analyzer, and the result of the measurement is used for adjusting the inflow of the carrier gas in each case. The method according to one item. The concentration of the sample gas is obtained from the concentration measurement before the sample gas enters the analyzer , and the result of the measurement is used for adjusting the inflow of the carrier gas each time. The method as described in any one of 2-8.   The method according to claim 1, wherein the concentration of the sample gas is determined from the thermal conductivity.   11. Method according to any one of claims 1 or 2-10, characterized in that the open split (22) operates on a co-current principle.   12. The method according to claim 1, wherein two or more sample gases are supplied to the open split (22), and the inflow of the carrier gas is adjusted for each sample gas. The method according to claim 1.   13. The gas chromatograph (21) is provided before the open split (22), and the outflowing gas is supplied to the open split as a sample gas. 13. The method described.   14. The sample gas according to claim 1, wherein the sample gas is divided into two or more partial gas streams before entering the open split (22), and this partial gas stream is fed to the open split. The method according to claim 1.   15. A method according to claim 14, characterized in that at least one partial gas stream is physically or chemically altered before entering the open split (22).   The at least one partial gas stream is guided through the trap (53) before entering the open split (22), thereby removing at least part of the components / substances contained in this partial gas stream The method according to claim 14 or 15. One or more of the sample gas A method according to claim 1, characterized in that it comprises a weight element to medium volume elements or compounds of these elements. 18. A method according to claim 17, characterized in that one or more compounds of said element can be transferred to the gas phase. The one or more sample gases are H2, CO2, CO, N2, SO2, N2O, NO, SF6, SF3, SO, Cl2, one or more compounds of noble gases. 18. The method according to 17. The method according to claim 17, wherein the one or more sample gases are one or more compounds of H, C, N, O, S, Cl. 21. The method according to claim 1, wherein the analyzer is a mass spectrometer (43) suitable for isotope ratio measurement. In any one of claims 1 or claim 2 to 21, characterized in that the sample gas and the standard gas is supplied to the analyzer without or carrier gas with a carrier gas via different open splits (100, 101) The method described. The supply of carrier gas to at least one of the two open splits is adjusted by dividing the carrier gas stream into a plurality of parallel partial gas streams, and one or more of the partial gas streams are selected to open splits. The method of claim 22 , wherein the method is provided. 24. The method of claim 23 , wherein some or all of the parallel partial gas streams are of different magnitudes. Claims sample gas, before being supplied to the open splits (100) to the flow to be guided to the open split, the split from the stream, characterized in that it is divided into a flow that is not supplied to the open splits 25. A method according to any one of claims 1 to 21, 23 and 24 . Comprising an open split (22), this open split having a mixing area (67) and a waiting area (68), and capillaries (31-33, 54-62) for sample gas, carrier gas and / or standard gas a) a capillary for taking out the gas (34) is arranged in the standby region, this time, is movable so as capillary return mixing zone (67) so as to approach the to or mixing zone within and again, wherein 26. An apparatus for supplying a gas to at least one analyzer for analyzing isotope ratios for carrying out the method according to any one of Items 1 to 25 , wherein two or more samples for a sample gas are used. A device characterized in that a capillary is provided and each capillary is provided with a unique drive for movement between the mixing zone and the waiting zone. 27. Device according to claim 26 , characterized in that the capillary drive is an actuator (35-38). 28. Device according to claim 26 or 27 , characterized in that the drive for the capillaries (31-34, 54-63) can be controlled by a common central control unit. 29. The device according to claim 26 or 27 and 28 , characterized in that the waiting area (68) has a larger cross-sectional area than the mixing area (67). 30. Device according to any one of claims 26 or 27-29 , characterized in that the cross-sectional area of the waiting area (68) is at least twice as large as the cross-sectional area of the mixing area (67). . The open split (22) has a funnel-shaped area between the mixing area (67) and the waiting area (68) having a substantially conical shape and the cross-sectional area being reduced towards the mixing area. 31. A device according to claim 26 or any one of claims 27-30 . 32. Device according to claim 26 or any one of claims 27 to 31 , characterized in that the length of the mixing zone (in the direction of the capillary) is greater than the width of the mixing zone (67). Standby position waiting area (68) for the capillary (34,63) for taking out the gas, according to claim 26 or claims, characterized in that close to the mixing region than the standby position of the other capillary (67) Item 33. The apparatus according to any one of Items 27 to 32 . Take-out position of the mixing zone (67) in for capillary (34,63) for taking out the gas, than mixing position of the other capillaries, characterized in that close to the waiting area (68) according to claim 26, wherein Item 34. The device according to any one of Items 27 to 33 . 35. Device according to claim 26 or 27 to 34 , characterized in that the capillaries (34, 63) for extracting gas are connected to a tube having a contraction point (65). 36. Device according to claim 26 or 27 to 35, characterized in that the capillaries (34, 63) for extracting gas are connected to a tube made of deactivated special steel. . 37. Device according to claim 26 or 27 to 36 , characterized in that the open split (22) is arranged in the analyzer. Open split (22) is co-current principle, i.e. the gas is adapted to flow only from the same direction, and claim 26 or claim 27 to, characterized in that one side is closed in the mixing zone (67) 38. Apparatus according to any one of 37 . Gas, ie the sample gas, carrier gas, for at least one of the standard gas, claim 26 or claim, characterized in that the capillary (31～33,54～62) is provided with different effective flow rate 27 A device according to any one of -38 . Gas, ie the sample gas, carrier gas, for at least one of the standard gas, claim 26 or claim, characterized in that the capillary (31～33,54～62) is provided having a different cross sectional area 27 40. Apparatus according to any one of. 41. Apparatus according to claim 26 or any one of claims 27 to 40, wherein the predetermined gas flow is adjustable in the gas pipe, the supply pipe (80) and at least one subsequent pipe ( 97) and a plurality of valves (89-96) provided between the supply pipe (80) and the subsequent pipe (97), the valves (89-96) being connected in parallel to each other, and A device that can be switched in stages, ie binary or incrementally. 42. Device according to claim 41 , characterized in that a specific throttle with a suitable flow rate is attached to each valve (89-96). 43. The apparatus of claim 42 , wherein the at least two valve throttles are different. 44. The apparatus according to claim 42 or 43 , wherein a plurality of different throttles are provided, and the flow rates of these throttles differ by the same multiple. 45. Apparatus according to any one of claims 41 or 42-44 , characterized in that the valves (89-96) are manually, electrically or electronically controllable. 43. A parallel pipe (136) without a valve is additionally provided for connecting the supply pipe (80) and the subsequent pipe (97). 46. The apparatus according to any one of 45 . 47. An open split (101) for mixing said gas flow and other gas flow arranged after a subsequent tube (97 or 113), according to claim 41 or 42 to 46 The device according to any one of the above. Comprising a subsequent second tube (capillary 125), and a plurality of valves (126) are arranged in parallel with each other between the subsequent second tube and the supply tube (80) according to 48. An apparatus according to any one of items 41 or 42-47 . 49. Device according to claim 48 , characterized in that each valve (126) is provided with a specific restriction (127-129) having a suitable flow rate. 50. Device according to claim 48 or 49 , characterized in that a second open split (100) is attached to the subsequent second tube (capillary 125). 50. A mass spectrometer according to claim 41 or 50 or any one of claims 42 to 49 , characterized in that a mass spectrometer is arranged as an analyzer after the one or more open splits (100, 101). apparatus. 42. Device according to claim 41 , characterized in that the supply pipe (80) comprises a branch (121) for bypassing the valve and for supplying directly to the open split (100).   A plurality of open splits (100, 101) or one of which has a first capillary (114) for supplying a high flow rate gas and a second capillary (120) for supplying a lower flow rate gas. 53. Apparatus according to claim 47 or any one of claims 41 to 46 and 48 to 52. The open split (100) comprises a capillary (119) for extracting gas, i.e. a degassing capillary, which is arranged in cocurrent with the first or second capillary (114, 120), and other 54. Device according to claim 53 , characterized in that it is arranged countercurrent to the capillaries (120, 114). 55. Apparatus according to claim 53 or 54 , characterized in that the second capillary (120) for supplying a low flow of gas is arranged in countercurrent to the degassing capillary (119). The degassing capillary (119) has an outer diameter smaller than the inner diameter of the second capillary (120) for supplying a low flow rate gas, and the degassing capillary and the second capillary are located at a position of both capillaries. 56. The apparatus of claim 55 , wherein the capillaries are relatively movable and coaxially disposed so that the capillaries fit together. One of the open split or a plurality of open splits (100, 101) is provided with a capillary (114) for supplying gas, and a branch that can be closed via a valve (124) ( 123). Apparatus according to claim 47 or 50 or claims 41 to 46 , 48 , 49 and 51 to 56 . One of the open split or the plurality of open splits (100, 101) has a capillary (114) for supplying gas, and two or more supply pipes (116, 117) lead to this capillary. 58. Apparatus according to claim 47 or 50 or claims 41 to 46 , 48 , 49 and 51 to 57 . The supply pipe (116, 117) is provided with a multi-way valve (118), which passes the gas toward the open split (100) at one switching position and discharges the gas at the other switching position. 59. The apparatus of claim 58 . The carrier gas can be supplied to two different open splits (100, 101) via the supply pipe (80), the sample gas can be supplied to one open split via the capillary, and the standard gas any one of claims 41 or claim 42 to 59 but wherein the can be supplied to the other open splits via capillary, that the degassing capillary from both open splits until analyzers are guided The device described in 1. 61. Apparatus according to claim 26 or any one of claims 27-60 ,
a) the first capillary (125) for the carrier gas is guided to the open split (100), b) the second capillary (120) for the low flow sample gas is guided to the open split (100),
c) The third capillary (114) for the sample gas having a higher flow rate is guided to the open split (100),
d) Device characterized in that the fourth capillary tube (119) is guided from the open split to the analyzer as a degassing tube. A carrier gas supply pipe (80) having a branch part (121) is disposed in front of the first capillary (125), and at this time, the branch part (121) is a second capillary (120) for low-flow sample gas. 62. The apparatus of claim 61 , wherein the apparatus is connected to. 63. Device according to claim 61 or 62 , characterized in that the fourth capillary (119) can be inserted as a degassing tube into the second capillary (120) for low flow sample gas.

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